U.S. patent application number 12/583418 was filed with the patent office on 2011-02-24 for stepped intensity electric road flare.
Invention is credited to Kevin McDermott.
Application Number | 20110043126 12/583418 |
Document ID | / |
Family ID | 43604793 |
Filed Date | 2011-02-24 |
United States Patent
Application |
20110043126 |
Kind Code |
A1 |
McDermott; Kevin |
February 24, 2011 |
Stepped intensity electric road flare
Abstract
A stepped intensity electric road flare having a housing
supporting a circuit. The circuit comprises an led light source, a
power controller and a power supply. The power controller energizes
the led light source with the power supply such that the led light
source emits a varying light having at least one perceived fixed
intensity within a range of emitted intensities. The road flare of
the present invention provides a perceived steady light having a
perceived fixed intensity during a portion or time zone of its
waveform thereby communicating its exact location. In addition
because its intensity changes during other portions or time zones
of its waveform it also demands attention. The present invention is
therefore an attention getting safety device communicating its
exact location. The present invention both alerts drivers to a
hazard and guides them past the hazard. In addition the emitted
light of the present invention is of a reddish color and
concentrated by an optic into a powerful light beam. An incendiary
road flare also emits a powerful light having a reddish color and,
at portions of its burn cycle, perceived as a steady light. An
incendiary road flare also varies its intensity during its burn
cycle. Therefore the electric road flare of the present invention
emits light having characteristics similar to the characteristics
of the light emitted by an incendiary road flare. The present
invention therefore both alerts and guides drivers with an
effectiveness similar to that of the incendiary road flare.
Inventors: |
McDermott; Kevin;
(Rockledge, FL) |
Correspondence
Address: |
KEVIN F MCDERMOTT
110 OYSTER PLACE
ROCKLEDGE
FL
32955
US
|
Family ID: |
43604793 |
Appl. No.: |
12/583418 |
Filed: |
August 20, 2009 |
Current U.S.
Class: |
315/291 |
Current CPC
Class: |
H05B 45/00 20200101;
B60Q 7/00 20130101; H05B 45/32 20200101; H05B 45/305 20200101 |
Class at
Publication: |
315/291 |
International
Class: |
H05B 41/36 20060101
H05B041/36 |
Claims
1. An electric road flare including: a housing supporting a
circuit; said circuit comprising an led light source, a power
supply and a power controller, said power controller varying a
power to said led light source from said power supply; and said
light source emitting a light, said light varying according to a
waveform of intensity versus time, said waveform comprising a
multiplicity of perceived substantially steady light zones mixed
with a multiplicity of varying light zones perceived as varying
from said perceived steady light zones whereby said road flare upon
being placed on a roadway about a hazard alerts a driver to the
hazard and guides him about the hazard.
2. An electric road flare according to claim 1 wherein said
electric road flare further comprises: an optic to concentrate said
light into a horizontal beam.
3. An electric road flare according to claim 1 wherein said
electric road flare further comprises: each of said perceived
substantially steady light zones generally having a dwell time
exceeding ten times a dwell time of each of said varying light
zones.
4. An electric road flare according to claim 1 wherein said
electric road flare further comprises: said light comprising a red
light.
5. An electric road flare according to claim 1 wherein said
electric road flare further comprises: said light source is
perceived as a continuously emitting light.
6. An electric road flare according to claim 1 wherein said
electric road flare further comprises: said perceived steady light
zones have a dwell time of at least 400 milliseconds.
7. An electric road flare according to claim 1 wherein said
electric road flare further comprises: said housing having a
predetermined configuration for a stable disposition on a
roadway.
8. An electric road flare including: a housing supporting a
circuit; said circuit comprising an led light source, a power
supply and a power controller, said power controller varying a
power to said led light source from said power supply; and said
light source emitting a light, said light varying according to a
waveform of intensity versus time, said waveform comprising a
multiplicity of lower intensity perceived substantially steady
light zones mixed with a multiplicity of upper intensity perceived
substantially steady light zones whereby said road flare upon being
placed on a roadway about a hazard alerts a driver to the hazard
and guides him about the hazard.
9. An electric road flare according to claim 8 wherein said
electric road flare further comprises: an optic to concentrate said
light into a horizontal beam.
10. An electric road flare according to claim 8 wherein said
electric road flare further comprises: each of said perceived lower
intensity substantially steady light zones generally having a dwell
time exceeding ten times a dwell time of each of said upper
intensity perceived steady light zones.
11. An electric road flare according to claim 8 wherein said
electric road flare further comprises: said light comprises a red
light.
12. An electric road flare according to claim 8 wherein said
electric road flare further comprises: said light source is
perceived as a continuously emitting light.
13. An electric road flare according to claim 8 wherein said
electric road flare further comprises: said perceived steady light
zones have a dwell time of at least 400 milliseconds.
14. An electric road flare according to claim 8 wherein said
electric road flare further comprises: said housing having a
predetermined configuration for a stable disposition on a
roadway.
15. An electric road flare including: a housing supporting a
circuit; said circuit comprising an led light source, a power
supply and a power controller, said power controller varying a
power to said led light source from said power supply; and said
light source emitting a light, said light varying according to a
waveform of intensity versus time, said waveform comprising a
multiplicity perceived substantially steady light zones mixed with
a multiplicity of perceived flickering light zones whereby said
road flare upon being placed on a roadway about a hazard alerts a
driver to the hazard and guides him about the hazard.
16. An electric road flare according to claim 15 wherein said
electric road flare further comprises: an optic to concentrate said
light into a horizontal beam.
17. An electric road flare according to claim 15 wherein said
electric road flare further comprises: each of said perceived
substantially steady light zones generally having a dwell time
exceeding ten times a dwell time of each of said perceived
flickering light zones.
18. An electric road flare according to claim 15 wherein said
electric road flare further comprises: said light comprising a red
light.
19. An electric road flare according to claim 15 wherein said
electric road flare further comprises: said light source is
perceived as continuously emitting light.
20. An electric road flare according to claim 15 wherein said
electric road flare further comprises: said perceived steady light
zones have a dwell time of at least 400 milliseconds.
21. An electric road flare according to claim 15 wherein said
electric road flare further comprises: said housing having a
predetermined configuration for a stable disposition on a
roadway.
22. An electric road flare including: a housing supporting a
circuit; said circuit comprising an led light source, a power
supply and a power controller, said power controller varying a
power to said led light source from said power supply; and said
light source emitting a light, said light varying according to a
waveform of intensity versus time, said waveform comprising a
multiplicity of perceived substantially steady light zones mixed
with a multiplicity of perceived pulsing light zones whereby said
road flare upon being placed on a roadway about a hazard alerts a
driver to the hazard and guides him about the hazard.
23. An electric road flare according to claim 22 wherein said
electric road flare further comprises: an optic to concentrate said
light into a horizontal beam.
24. An electric road flare according to claim 22 wherein said
electric road flare further comprises: each of said perceived
substantially steady light zones generally having a dwell time
exceeding ten times a dwell time of each of said perceived pulsing
light zones.
25. An electric road flare according to claim 22 wherein said
electric road flare further comprises: said power supply is a
battery contained within said housing.
26. An electric road flare according to claim 22 wherein said
electric road flare further comprises: said perceived steady light
zones have a dwell time of at least 400 milliseconds.
27. An electric road flare according to claim 22 wherein said
electric road flare further comprises: said housing having a
predetermined configuration for a stable disposition on a
roadway.
28. An electric road flare including: a housing supporting a
circuit; said circuit comprising an led light source, a power
supply and a power controller, said power controller varying a
power to said led light source from said power supply; and said
light source emitting a light, said light varying according to a
waveform of intensity versus time, said waveform comprising a
multiplicity of perceived substantially steady light zones mixed
with a multiplicity of perceived flashing light zones whereby said
road flare upon being placed on a roadway about a hazard alerts a
driver to the hazard and guides him about the hazard.
29. An electric road flare according to claim 28 wherein said
electric road flare further comprises: an optic to concentrate said
light into a horizontal beam.
30. An electric road flare according to claim 28 wherein said
electric road flare further comprises: each of said perceived
substantially steady light zones generally having a dwell time
exceeding ten times a dwell time of each of said perceived flashing
light zones.
31. An electric road flare according to claim 28 wherein said
electric road flare further comprises: said light comprising a red
light.
32. An electric road flare according to claim 28 wherein said
electric road flare further comprises: said perceived steady light
zones have a dwell time of at least 400 milliseconds.
33. An electric road flare according to claim 28 wherein said
electric road flare further comprises: said housing having a
predetermined configuration for a stable disposition on a
roadway.
34. An electric road flare according to claim 28 wherein said
electric road flare further comprises: said flashing light zones
perceived as continuously emitting said light.
35. A warning system including: at least three road flares, each
said road flare including a housing supporting a circuit; each said
circuit comprising an led light source, a power supply and a power
controller, said power controller varying a power to said led light
source from said power supply; and each said light source emitting
a light, said light varying according to a waveform of intensity
versus time, said waveform comprising a multiplicity of perceived
steady light zones mixed with a multiplicity of steady light zones
perceived as varying from said perceived steady light zones whereby
said road flares upon being placed on a roadway about a hazard
alert a driver to the hazard and communicate a distinct line of
lights for guiding the driver past the hazard.
Description
[0001] As a result of the similar light emitting characteristics
oncoming drivers give the present invention the respect, attention
and reaction afforded the incendiary road flare enhancing its
ability to guide drivers safely past hazardous zones.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] This invention relates to a lighting device used primarily
as a warning device or road flare. The device is normally stored in
the trunk of an emergency vehicle until it is needed to alert
oncoming drivers of a hazard in the road. It is commonly used by
first responders such as policeman or fireman however it can be
used by private citizens as well. In an emergency the user removes
the light from his vehicle and places it in the road to signal to
approaching vehicles the fact that a hazard exists. It is common
practice for several of these devices to be placed in the roadway
forming a wedge to guide approaching vehicles around the hazard.
Currently both incendiary and electric road flares are in use.
[0004] Federal highway laws controlled by the National Highway
Traffic Safety Administration (NHTSA) included primarily in section
125 detail the requirements for warning lights in and around long
term hazardous areas and job sites. In general these laws require
electric lights that flash from "ON" to "OFF" when alerting drivers
of a hazard. Lights that flash from "ON" to completely "OFF" are
effective in drawing a driver's attention to a hazard. Flashing
lights that flash completely "OFF" are especially effective in
drawing a driver's attention and that is why the requirement for
flashing lights exists. On the other hand electric lights emitting
a steady "ON" light are specified when guiding drivers through a
work zone. The steady "ON" lights have a perceived fixed intensity.
They continuously communicate to a driver their exact location and
are therefore effective in guiding a driver through a work zone.
When guiding drivers through a hazard zone "ON-OFF" flashing lights
are not normally employed as they can create confusion.
[0005] The federal law also requires the electric lights to be
positioned from two to four feet above the roadway and mounted on
barricades or on cones. These lights are bulky and usually too
large to store within the limited space available on many emergency
vehicles. In addition if struck by an oncoming vehicle they can
damage the vehicle or if projected through the air, strike a first
responder.
[0006] The federal laws to not apply to short term hazards such as
a disabled vehicle or at the scene of a small accident. This
results from the fact that it would require excessive time and
equipment to set up the safety lights required by federal law for a
long term hazard zone when marking a short term hazard.
[0007] The devices employed to identify short term hazards must be
compact, easy to deploy and easy to retrieve. Historically
incendiary road flares have filled this need. Electric road flares
are currently replacing them in many situations.
[0008] Finally it is noteworthy to realize that emitted light is
not always equal to perceived light. This is common knowledge to
those in the field of lighting. Throughout this specification we
have indicated the differences and how it applies to the
concepts.
[0009] 2. Prior Art
[0010] Prior art identification of short term hazard zones includes
small electric lights, electric road flares or incendiary road
flares that are normally placed directly on the road. The electric
road flares are usually designed to be run over by oncoming
vehicles without sustaining damage or being projected by an
impinging vehicle towards a first responder. These small electric
road flares are currently replacing prior art incendiary road
flares because they avoid the burn hazards and toxic fumes created
by incendiary pyrotechnic devices.
[0011] Incendiary road flares have a number of deficits. However
incendiary road flares are excellent warning devices as they are
highly visible warning devices which both alert and guide oncoming
drivers. Incendiary road flares are powerful red light sources,
constantly illuminating. During portions of their burn cycle they
emit a steady light having a substantially fixed intensity. The
incendiary road flare by having a fixed intensity and by being
disposed directly on a roadway communicates its exact location
relative to a hazard thereby improving a driver's ability to avoid
an accident. However, during other portions of their burn cycle
they can flare increasing their intensity. Their intensity
therefore steps changing its value during their operation. The
varying intensity alerts drivers to their presence. Incendiary
flares are dangerous and hot. Drivers realize that the incendiary
road flares are dangerously hot and tend to respect them. Drivers
move as directed when incendiary road flares are in position.
[0012] The prior art electric flares currently being substituted
for incendiary flares are not as effective in controlling traffic
as the incendiary flares. Many are far less intense. All have light
emission patterns differing from the substantially steady on,
continuously emitting and randomly varying light of the incendiary
flares. The prior art electric flares do not, like incendiary
flares, both alert and guide oncoming drivers.
[0013] Prior art designs employ either a single led light source or
a plurality of led light sources in a circle. The single led light
source design is usually less expensive to manufacture. The prior
art electric flares having a single led light source are either
steady "ON", flashing from full "ON" to full "OFF" or flickering
rapidly from "ON" to "OFF". When in the flashing mode and in the
"ON" zone of its waveform the flashing light can have a dwell time
long enough for a driver to progress towards perceiving the light
as having a fixed intensity. Unfortunately, when in the "OFF" zone
of its waveform the dwell time is usually also long such that the
light visually disappears. The long "OFF" zone of the flashing
waveform which follows the "ON" time ceases communication with the
driver for an unacceptably long time such that the drivers eyes
wander thereby losing his progress in establishing and exact
location for the light or the hazard. In addition a group of
flashing lights combine to make it more difficult for a driver to
focus on any one of the lights to discern its fixed intensity.
[0014] If the period of the flash cycle of a light in a flash mode
is reduced the light will be perceived first as a rapidly pulsing
light then as a flickering light neither of which would be
perceived as having a fixed intensity. A rapidly pulsing light is
perceived as emitting a light having an effect between flashing and
flickering whereby it visibly changes from "ON" to "OFF" but
changes quickly such that its "ON" zone is not perceived as having
a fixed intensity.
[0015] In the perceived steady "ON" mode of the prior art single
led the led is usually not continuously emitting light but is
pulsed from full "ON" to full "OFF" with an "ON" dwell time or "ON"
zone of approximately 2 milliseconds and an "OFF" dwell time or
"OFF" zone of approximately 3 milliseconds. The human eye
integrates this pulsing light and, due to its short 5 millisecond
period, perceives a steady "ON" warning light having a fixed
intensity. This high frequency pulse light which is perceived as a
steady light having a perceived fixed intensity is excellent for
guidance as is an emitted steady "ON" light, however like an
emitted steady light is inadequate for alerting.
[0016] In the flickering mode of the single led prior art design,
the emitted light is controlled by a microcontroller such that the
led lamp is flashing from full "ON" to full "OFF" with random
pulses such that its "ON time varies from approximately 5 to 30
milliseconds and its "OFF" time varies from approximately 5 to 30
milliseconds. In this prior art design the "ON" and "OFF" times of
the led are such that the human eye integrates the pulses to
visualize a light that is continuously emitting but is not
perceived as a steady light because it has no perceived fixed
intensity. It is, in fact, visualized as a constantly changing
intensity. This flicker mode, like a slow pulsing or flashing mode,
is good for alerting but due to its constantly changing perceived
intensity, can confuse a driver attempting to establish its exact
position for guidance past a hazard. This prior art design could
have the frequency of the pulses of the flicker mode decreased such
that the "ON" time for the led was sufficient for a driver to
perceive a fixed intensity and establish the exact location of the
light. However decreasing the frequency would also lengthen the
"OFF" time making the design a typical flashing light with the
emitted light perceived as either steady "ON" or fully "OFF".
[0017] This perception of a rapidly pulsing light as a steady light
is to be expected and is described in numerous technical sources
including the reference book of the Illuminating Engineering
Society. Specifically, when a rapidly pulsing light is pulsed at a
frequency which exceeds a parameter identified as the critical
flicker frequency relative to that design the human eye perceives
the pulsing light as steady light. The exact value of the critical
flicker frequency for a design depends upon a number of factors
including intensity and waveform. The frequency of the pulses in
the steady "ON" mode of the prior art design far exceeds the
critical flicker frequency of that waveform and therefore the prior
art pulsing light is perceived as a steady light having a perceived
fixed intensity.
[0018] Similarly, in the flicker mode of the prior art design the
led is not "ON" constantly but pulsing rapidly from "ON" to fully
"OFF". The stated objective of this prior art design is a flicker
mode. This flicker effect is achieved by designing the pulse
frequency to be less than the critical flicker frequency. Using
this design frequency the emitted light is perceived by the human
eye as flickering. A flickering light is good for alerting. However
as long as it is flickering it is not perceived by the human eye as
having a fixed intensity. A perceived flickering light having no
zone or portion of its cycle discernable as a fixed or discrete
intensity fails to convey its exact location to an oncoming driver.
It fails to provide a portion of its cycle having the steady light
or visually fixed intensity necessary to accurately establish its
location. A plurality of flickering lights further adds to the
confusion as a driver looks for guidance past a hazard.
[0019] The single led prior art design offers three separate
waveforms of emitted light defined as operating modes including, a
pulsed steady "ON", a pulsed "FLASH" and a pulsed "FLICKER" mode.
It does not disclose a single mode or waveform combining the prior
art modes to improve the effectiveness of the light by both
alerting and guiding oncoming drivers.
[0020] A second type of prior art electric flare employs a
plurality of led light sources positioned in a circle. The
plurality of led light sources are energized in sequence to create
a rotating effect. In this rotating effect design each led lamp
actually flashes from "ON" to "OFF" with the sequential
illumination creating the rotating effect. Prior art flares having
a rotating effect can confuse rather than guide oncoming
drivers.
[0021] The prior art rotating effect designs usually also include
the option of simultaneously flashing the entire circle of led
light sources from "ON" to completely "OFF" or simultaneously
energizing the entire circle using a high frequency pulse to create
a perceived steady "ON" mode. It is noteworthy to realize that the
prior art rotating effect electric road flares and the single led
light source road flares both usually incorporate an led light
source, a power controller, a power supply and a housing. In
addition the power controller is usually a microcontroller which is
a programmable computer. It would therefore be possible for prior
art to adjust their computer program to include a perceived steady
light having a discrete intensity combined with a stepped intensity
to achieve the objectives of the present invention. They have not
included this option as part of their design.
[0022] The prior art electric road flares have steady or flashing
modes similar to the lights meeting federal laws regarding long
term hazards. They perform as either guiding or alerting warning
devices but not both simultaneously as is accomplished by both the
incendiary road flare and the present invention.
[0023] The prior art road flare light emission patterns are not
visually similar to the incendiary flares and therefore they do not
receive the drivers respect required for this type of warning
device.
[0024] Prior art does not include the additional features: [0025]
Prior art does not provide an electric road flare having a housing
for disposition on a roadway, emitting a light perceived as a
steady light during a first multiplicity of zones of its waveform
and emitting a visible light perceived as different from said
perceived steady light during a second multiplicity of zones of its
waveform. The second multiplicity of zones alternating with the
first multiplicity of zones thereby providing an alerting signal as
well as guidance about a fixed hazard. [0026] Prior art does not
provide an electric road flare having a housing for disposition on
a roadway, emitting a light perceived as a steady light during a
first multiplicity of zones of its waveform and emitting a visible
light perceived as a flickering light during a second multiplicity
of zones of its waveform. The second multiplicity of zones mixed
with the first multiplicity of zones thereby providing an alerting
signal as well as guidance about a fixed hazard. [0027] Prior art
does not provide an electric road flare having a housing for
disposition on a roadway, emitting a light perceived as a lower
intensity steady light during a first multiplicity of zones of its
waveform and emitting a light perceived as an upper intensity
steady light during a second multiplicity of zones of its waveform.
The second multiplicity of zones mixing with the first multiplicity
of zones thereby providing an alerting signal as well as guidance
about a fixed hazard. [0028] Prior art does not provide an electric
road flare having a housing for disposition on a roadway, emitting
a light perceived as a steady light during a first multiplicity of
zones of its waveform and emitting a visible light perceived as a
pulsing light during a second multiplicity of zones of its
waveform. The second multiplicity of zones alternating with the
first multiplicity of zones thereby providing an alerting signal
and guidance about a fixed hazard. [0029] Prior art does not
provide an electric road flare having a housing for disposition on
a roadway, emitting a light perceived as a steady light during a
first multiplicity of zones of its waveform and emitting a visible
light perceived as a flashing light during a second multiplicity of
zones of its waveform. The second multiplicity of zones mixed with
the first multiplicity of zones thereby providing an alerting
signal and guidance about a fixed hazard. [0030] Prior art does not
provide a group of electric road flares for disposition on a
roadway, each flare emitting a continuously visible light having a
multiplicity of alerting signal zones mixed or alternating with a
multiplicity of perceived steady light or fixed intensity zones
thereby providing a plurality of alerting signals and a distinct
visual line of lights for guidance about a fixed hazardous zone
OBJECTS AND ADVANTAGES
[0031] The objects and advantages of the present invention are to
improve upon the safety of the prior art electric road flares. The
present invention is often used in groups of three to eight placed
on the roadway to define short term hazards. This hazard warning
system is unlike the system employed for long term hazard zones
which usually employ a large number of flashing and steady electric
lights mounted well above ground level on barricades. Therefore the
present invention must provide an emitted light which is effective
in guiding drivers past a hazard and also effective in alerting
them to the existence of a hazard. Since the incendiary road flare
historically used achieves these objectives one objective of the
present invention is to make the electric road flare emit light
having the characteristics of an incendiary road flare and to
appear to an oncoming driver similar to an incendiary road
flare.
[0032] In order to achieve this objective the present invention is
designed to emit a light having an emitted red color similar to
that of an incendiary flare and further designed to emit a
concentrated powerful light beam similar to an incendiary flare. It
is additionally designed to emit a stepped intensity light having
at least one perceived fixed intensity. By providing a road flare
emitting a stepped intensity red light having at least one fixed
intensity concentrated into a powerful beam the present invention
achieves the excellent visibility and safety features of the
incendiary road flare without its dangerous deficits. In addition
by appearing similar to an incendiary flare the present invention
receives the attention and respect of oncoming drivers without the
dangerous side effects of the incendiary flares.
[0033] In order to achieve the desired objectives the present
invention employs a circuit having a power controller energizing an
led light source with a power supply. The power controller which is
usually a microcontroller is programmed to energize the led light
source with a power varying within a predetermined range. The led
light source is energized such that the intensity of the road flare
changes but also at times remains constant long enough such that
during the perceived constant intensity zone of the waveform
representing the emitted light the light is perceived as being
emitted at a fixed intensity. Optionally, the intensity of the led
light source can step to a higher intensity and similarly remain
constant at that intensity long enough to be perceived as being
emitted at a second distinct intensity. In that design the emitted
intensity remains within a visually perceived range of intensities.
Thus, an oncoming driver can easily establish the exact location of
the road flare on the road relative to a hazard even though the
flare is demanding his attention by having a varying intensity.
[0034] Further objects and advantages are realized through
combinations of the above distinct advantages.
SUMMARY
[0035] In accordance with the present invention an electric road
flare comprises a circuit having an led light source, a power
supply and a power controller. The circuit is supported by a
housing. The power supply energizes the led light source with a
varying power such that during a first multiplicity of zones of the
intensity versus time waveform of the emitted light the emitted
light is perceived as a steady light and during a second
multiplicity of zones mixed with said first multiplicity of zones
the emitted light is perceived as a visible light varying from the
perceived steady light. The varying intensity among light zones
alert an oncoming driver to a hazard and the perceived steady light
zones guide him past the hazard.
DRAWINGS
Figures
[0036] FIG. 1 is a perspective view of road flare 25 according to
the present invention
[0037] FIG. 2 is a top view of the road flare of FIG. 1
[0038] FIG. 3 is a partial cross section taken across line 3-3' of
FIG. 2
[0039] FIG. 4 is a perspective view of the circuit assembly from
FIG. 3
[0040] FIG. 5 is an electrical schematic of the circuit of FIG.
4
[0041] FIG. 6 is a top view of a typical roadway hazard scene
employing four FIG. 1 road flares to prevent an accident
[0042] FIG. 7 is an intensity versus time diagram of the light
emitted from the road flare of FIG. 1
[0043] FIG. 8 is an intensity versus time diagram of the light
emitted from a prior art light in steady "ON" mode
[0044] FIG. 9 is an intensity versus time diagram of the light
emitted from a prior art light in a flicker mode
[0045] FIG. 10 is an intensity versus time diagram similar to FIG.
7 except that high frequency pulses are employed in the upper and
lower intensity zones
TABLE-US-00001 [0046] DRAWINGS - Reference Letters DRAWINGS -
Reference Numerals C1 Obstructing Car 1 housing 2 circuit assembly
C2 Approaching Car 3 top 4 base D Drain 5 external threads 6
internal threads E Light Emitting Element 7 circuit board 8A screw
GA Gate 8B screw 9 o-ring GR Ground 10A negative battery 10B
positive battery contact HB Horizontal Light Beam contact HD
Housing Base Diameter 11 spacer circuit board 12 plano convex lens
HH Housing Height 13 microcontroller 14 battery HR Horizontal Road
15 switch 16 led I Intensity Function 17 resistor 18 resistor I1
Upper Intensity of Current 19 resistor 20 mosfet Invention 21 22 I2
Lower Intensity of Current 23 24 Invention 25 road flare I3 Upper
Intensity of Prior Art Steady Waveform W2 I4 Upper Intensity of
Prior Art Flicker Waveform W3 I5 Upper Intensity of Current
Invention with Pulsed Waveform I6 Lower Intensity of Current
Invention with Pulsed Waveform K1 Pulse of Light within Upper
Intensity Zone U1P K2 Pulse of Light within Upper Intensity Zone
U1P K3 Pulse of Light within Upper Intensity Zone U1P K4 Pulse of
Light within Upper Intensity Zone U1P K5 Pulse of Light within
Lower Intensity Zone L1P K6 Pulse of Light within Lower Intensity
Zone L1P K7 Pulse of Light within Lower Intensity Zone L1P L1 Lower
Intensity Zone of Period P1 L1P Lower Intensity Zone of Period P1P
L2 Lower Intensity Zone of Period P2 L2P Lower Intensity Zone of
Period P2P L5 Lower Intensity Zone of Period P5 L8 Lower Intensity
Zone of Period P8 L9 Lower Intensity Zone of Period P9 P1 Period of
Waveform W1 P1P Period from Waveform W1P P2 Period of Waveform W1
P2P Period of Waveform W1P P5 Period of Waveform W2 P8 Period of
Waveform W3 P9 Period of Waveform W3 PG Ground Pin PI Input Pin PKL
Period of Pulses K5 thru K7 within Lower Intensity Zone L1P of
Waveform W4 PKU Period of Pulses K1 thru K4 within Upper Intensity
Zone U1P of Waveform W4 PO Output Pin R1 Road Flare 1 R2 Road Flare
2 R3 Road Flare 3 R4 Road Flare 4 S Source T Time Function U1 Upper
Intensity Zone of Period P1 U1P Upper Intensity Zone of Period P1P
U2 Upper Intensity Zone of Period P2 U2P Upper Intensity Zone of
Period P2P U3 Upper Intensity Zone of Period P3 U4 Upper Intensity
Zone of Period P4 U5 Upper Intensity Zone of Period P5 U6 Upper
Intensity Zone of Period P6 U8 Upper Intensity Zone of Period P8 U9
Upper Intensity Zone of Period P9 VB Battery Voltage W1 Waveform of
Present Invention W2 Waveform of Prior Art Steady "ON" Mode W3
Waveform of Prior Art "Flicker" Mode W4 Pulsed Waveform Alternative
for Waveform W1 XLP1 Lower Dwell Time for Period P1 XLP1P Lower
Dwell Time for Period P1P XUP1 Upper Dwell Time for Period P1 XUP1P
Upper Dwell Time for Period P1P XLP5 Lower Dwell Time for Period P5
XUP5 Upper Dwell Time for Period P5 XLP8 Lower Dwell Time for
Period P8 XUP8 Upper Dwell Time for Period P8
OPERATIONAL DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1-7
[0047] Electric road flare 25 of FIGS. 1 through 7 is the preferred
embodiment of the present invention. FIG. 1 is a perspective view
of road flare 25. FIG. 2 is a top view of FIG. 1 and FIG. 3 is a
partial cross sectional view across line 3-3' of FIG. 2. Looking at
FIGS. 1 through 3 road flare 25 comprises housing 1 supporting
circuit assembly 2. Housing 1 comprises top 3 molded of a
transparent resin and base 4 also molded of a resin. Housing 1
comprises a predetermined configuration for a stable disposition on
a roadway. The predetermined configuration comprises a low profile
and large diameter of housing 1 wherein the ratio of the housing
base diameter HD to the housing height HH exceeds two. Top 3 has
external threads 5 which mate with internal threads 6 on base 4 to
permit easy assembly of housing 1. O-Ring 9 seals top 3 to base 4.
Housing 1 supports circuit assembly 2 which includes circuit board
7 fastened to top 3 with screw 8A and screw 8B. Circuit board 7
includes negative battery contact 10A and positive battery contact
10B for connecting battery 14 for energizing circuit assembly 2.
Led 16 is connected to spacer circuit board 11 which in turn is
connected to circuit board 7 so that led 16 is positioned with its
light emitting element E at focal point F of circular plano convex
lens 12 molded as part of top 3. Light emitted from led 16
intersects plano convex lens 12 to be redirected to form horizontal
light beam HB directed throughout a 360 degree azimuth.
[0048] FIG. 4 is a diagrammatic perspective view of circuit
assembly 2 removed from FIG. 3. FIG. 5 is an electrical schematic
of circuit assembly 2. Circuit board 7 of FIG. 2 does not show many
of the electronic components of FIG. 5 as these can have numerous
locations and are easily positioned by one skilled in the art. In
FIG. 5 circuit assembly 2 comprises a power controller,
specifically in circuit assembly 2, microcontroller 13 (Cypress.TM.
Semiconductor PIN cy8c21123-24sxi), battery 14 (a 3 volt lithium
battery having battery voltage VB), switch 15 (an ON-OFF push
button switch), led 16 (a red light emitting surface mount led lamp
CREE.TM. P/N XRE), resistors 17, 18 and 19 and mosfet 20 (Zetex.TM.
P/N zxmn6a07 fta). Using typical design techniques circuit board 7
will include the means to support and connect all of the components
of circuit assembly 2 to effect the electrical schematic of FIG.
5.
[0049] Microcontroller 13 is flashed with program code to function
as an oscillator that toggles the voltage at output pin PO between
battery voltage VB of battery 14 and zero volts with a randomly
generated duty cycle. With switch 15 closed microcontroller 13 is
energized at input pin P1 and toggles the voltage at output pin PO
relative to ground pin PG and to ground GR. When the voltage at
output pin PO is equal to battery voltage VB gate GA--source S
junction of mosfet 20 is forward biased which in turn allows
current to flow through drain D--source S junction. This allows the
maximum predetermined current flow through led 16 and resistor 17
to ground GR. When the voltage at output pin PO is zero mosfet 20
is turned "OFF". Gate GA--source S junction of mosfet 20 is
therefore not forward biased. Resistor 19 pulls gate GA of mosfet
20 to ground GR. This prevents current from flowing through drain
D--source S junction of mosfet 20. Instead of flowing through
mosfet 20 the current flows through resistor 18 which illuminates
led 16 with the minimum predetermined current. Microcontroller 13
is programmed to continually randomly toggle the voltage at output
pin PO as long as switch 15 is closed. This circuit creates a
stepped intensity random period emitted light which continuously
emits light having waveform W1 of FIG. 7 to be described later. One
skilled in the art would easily be able to set the predetermined
currents and to provide the required program code. There are
numerous other electronic circuits which can achieve the desired
result of having led 16 emit a continuously visible stepped
intensity random period emitted light having at least one perceived
fixed intensity. Adjustments to the program code and circuit can
change the predetermined maximum and minimum current applied to led
16. Microcontroller 13 varies the current and therefore the power
supplied to led 16. The power supplied to led 16 determines the
waveform of the emitted light. Hence, the predetermined range of
current supplied by microcontroller 13 to led 16 establishes a
predetermined range of power resulting in a predetermined waveform
of emitted light and a range of intensity of the light emitted by
led 16. A person skilled in the art can design circuit assembly 2
or alternatively use other circuit designs to provide a road flare
emitting light at a high or upper intensity for a predetermined
higher intensity dwell time and a lower intensity for a
predetermined lower intensity dwell time. The present invention
would require that the dwell time of at least one of the levels of
intensity be sufficiently long such that a typical human eye will
perceive it as a steady light having a fixed intensity. The lower
intensity is usually the intensity with the long dwell time as this
is the intensity used to guide a driver past a hazard. The
predetermined dwell time adequate for a particular use can be
easily programmed into microcontroller 13 with the optimal value
for this parameter determined by a number of use factors such as
color of emitted light, ambient lighting, vehicle speeds, etc.
Dwell times of at least 400 milliseconds for the lower intensity
have, for some uses, been found acceptable. Longer dwell times
improve the ability of a driver to establish that the light is
steady and to thereby determine its location. However shorter lower
intensity dwell times beneficially reduce the elapsed time between
the alerting effect of the upper intensity zones. Therefore, the
lengths of the upper and lower intensity dwell times and the ratio
between them will effect the ability of the road flare to direct
drivers past the hazard. The optimum values for the dwell times
will be a function of a number of variables including vehicle speed
and ambient light. However, the lower intensity dwell time should,
in most designs, generally exceed four times the upper intensity
dwell time.
[0050] FIG. 6 is a top view of a typical use for road flare 25 on a
horizontal road HR where obstructing car C1 is inoperable and road
flares R1, R2, R3 and R4 similar to road flare 25 are placed in a
wedge formation to direct approaching car C2 safely around. Road
flare 25 is constructed with a wide base, low profile and low
center of gravity so that it can be placed on a road and resist
displacement by wind or vibration. In addition due to its
predetermined configuration it can withstand accidental run over by
approaching vehicles and resist being accidentally knocked from its
position on the road. Road flare 25 is placed directly on a road to
indicate hazards such as disabled cars, pot holes, etc. Once placed
it has a fixed relationship on the road relative to the hazard.
Oncoming drivers using the steady light zones of the emitted light
waveform can establish the exact location of each of road flares R1
through R4 and therefore can see a distinct line of lights
indicating the exact path to follow relative to the hazard to avoid
the hazard. This advantage would be seriously degraded if road
flares R1 through R4 were placed on a barricade several feet above
ground level as required by NHTSA for long term hazards. The
relationship between road flares R1 through R4 and the hazard would
change drastically due to their height above the road as the
oncoming driver approached the hazard. Thus the combination of
placing the road flares on the road and the road flares emitting a
perceived steady light is of significant value when guiding a
driver past a hazard. The stepped intensity of the present
invention additionally alerts the driver making the present
invention a superior safety device.
[0051] FIG. 7 is an intensity I versus time T diagram of waveform
W1 of the light emitted from road flare 25 of FIG. 1. FIG. 7 shows
waveform W1 which represents the light actually emitted during two
periods of emitted intensity. The relationship between emitted
light and perceived light will be related to the waveform and will
be discussed as we proceed. Period P1 emits light at upper
intensity zone U1 of waveform W1 at upper intensity I1 having an
upper dwell time XUP1 followed by lower intensity zone L1 of
waveform W1 in which the intensity is reduced to lower intensity I2
for lower dwell time XLP1. This is followed by period P2 which
emits light at upper intensity zone U2 at upper intensity I1 for an
upper dwell time XUP2 followed by lower intensity zone L2 in which
the intensity is reduced to lower intensity I2 for lower dwell time
XLP2. Road flare 25 continues to emit light according to waveform
W1 and waveform W1 continues with additional similar random periods
which are not shown. Thus as represented by waveform W1 the emitted
light from led 16 randomly varies such that both the upper
intensity zones and the lower intensity zones are periodic with
irregular periods. In the present embodiment of the current
invention the periods are irregular and randomly change. The shape
of waveform W1 can change and still represent a design employing
the concepts of the current invention. It could, for example, be
acceptable for the periods to be regular or nonrandom. It could
also be acceptable for some alternate types of zones to be mixed
within waveform W1. Hence, even though the shape of waveform W1
varies it is limited to predetermined parameters which are selected
such that the emitted light complies with the stated objectives of
the present invention.
[0052] Since in accordance with basic optics the frequency is
defined as the inverse of the period and since periods P1 and P2
are varying the frequency varies. In the present invention the
period and therefore the frequency is programmed to randomly vary.
In the present invention the waveforms and periods are
predetermined such that when the light is in a lower intensity zone
portion of waveform W1 such as lower intensity zone L1 its dwell
time, such as lower dwell time XLP1, is long enough for an oncoming
driver to perceive it as a substantially steady light having a
substantially fixed intensity. In perceiving the emitted light as
at a substantially fixed intensity or equivalently as a steady
light during a predetermined length of time the driver will be able
to establish its discrete location on the road relative to the
hazard and thereby avoid running over the light or more importantly
running into the hazard. It is noteworthy to realize that since the
emitted light will be stepping between at least two intensity
levels the perceived intensity may not always be the same as the
emitted intensity of FIG. 7. The differential between the actual
and perceived intensities will depend upon many factors including
waveform, intensity levels, etc. Nevertheless the long dwell times
of the lower intensity zones of waveform W1 combined with the
unchanging intensity within each lower intensity zone effectively
equalize the actual and perceived intensities of the light emitted
during the lower intensity zones of the waveform. By providing a
substantially perceived steady light having a perceived fixed
intensity in the lower intensity zones of waveform W1 the present
invention communicates its distinct location on the road relative
to a hazard to oncoming drivers thereby providing the guidance
necessary to reduce accidents.
[0053] In addition to providing guidance using light emitted during
lower intensity zone L1 road flare 25 alerts drivers using light
emitted during upper intensity zone U1 of waveform W1. Looking
again at upper intensity zone U1 the upper intensity dwell time
XUP1 can be short because upper intensity zone U1 is included to
alert rather than guide the driver. The driver does not have to
perceive the light emitted during upper intensity zone U1 as
steady. The high intensity and short dwell time of upper intensity
zone U1 effectively alerts the driver. Waveforms having lower
intensity dwell times which exceed ten times the upper intensity
dwell times represent one class of designs which employ the
concepts of the present invention. The long lower intensity or
fixed intensity dwell time assures the driver or observer the time
needed to establish the exact location of the road flare. A very
short upper intensity or alerting light zone dwell time assures
that the driver will not lose the location of the road flare. The
fact that the upper intensity zone usually comprises a short dwell
time relative to the lower intensity or steady light zone coupled
with the fact that light is perceived as continuously emitted
during both the upper and lower intensity zones makes it easy for a
driver to establish and maintain the location of road flare 25.
[0054] Upper intensity zone U1 can, within the scope of the present
invention, comprise any of a variety of waveforms each designed to
accomplish a specific effect. For example a series of short pulses
of light can be included to create a flicker effect within upper
intensity zone U1. Alternatively the dwell time of upper intensity
zone U1 can be selected as shown in FIG. 7 such that a driver can
perceive it as a steady light having a perceived fixed intensity
thereby adding to the effect of lower intensity zone L1 in
identifying an exact location of road flare 25. It is to be noted
that establishing a long dwell time for upper intensity zone U1
such that a driver perceives it as a steady light permits a driver
to define the exact location of road flare 25 at all times during
its waveform.
[0055] Thus upper intensity zone U1 can be designed to comprise a
single short pulse of high intensity light, a series of quick
pulses, a flicker effect, a series of lengthened dwell time pulses
to create a high intensity-low intensity flash or a high intensity
long dwell time zone creating a high intensity fixed intensity
light to be used for guidance and warning. Road flare 25 therefore
emits a perceived steady light having a perceived intensity during
the lower intensity zone L1 of waveform W1 and also emits a light
distinct from the perceived steady light during an upper intensity
zone U1 of waveform W1. Finally it is acceptable for waveform W1 to
include additional high intensity zones or other light emitting
zones conforming with the dual objectives of alerting and guiding
as disclosed in this specification.
[0056] The lower intensity zone L1 is included to define the
location of road flare 25 and guide the driver past the hazard.
Lower intensity zone L1 does not consist of a flicker effect
waveform as found in prior art because the flicker effect does not
provide the driver with the visual information required for him to
establish the distinct location of road flare 25. In FIG. 7--which
is diagrammatic only and not drawn exactly to size--period P1 is
1000 milliseconds, period P2 is 1200 milliseconds, upper dwell time
XUP1 for period P1 is 150 milliseconds and upper dwell time XUP2
for period P2 is 200 milliseconds. Lower dwell time XLP1 for period
P1 is 850 milliseconds and lower dwell time XLP2 for period P2 is
1000 milliseconds. Other dwell times for the parameters and zones
in FIG. 7 can be employed while still implementing the concepts of
the present invention.
[0057] FIG. 8--which is diagrammatic and not drawn exactly to
size--is an intensity versus time diagram of the light emitted from
a prior art light in a steady "ON" mode. In FIG. 8 waveform W2
comprises a series of identical high intensity high frequency
pulses of light including upper intensity zone U4, upper intensity
zone U5 and upper intensity zone U6. Period P5 of waveform W2 is
typical and comprises upper intensity zone U5 emitting light at
upper intensity I3 having an upper intensity dwell time of XUP5.
Period P5 also includes lower intensity zone L5 having zero
intensity and lower intensity dwell time XLP5. Waveform W2 is a
typical prior art pulsed waveform with a period P5 of 5
milliseconds. This type of waveform is found in many led lights. It
emits light in rapid pulses but is perceived by the human eye as a
steady light of a fixed intensity. The human eye perceives a
pulsing or flickering light as a steady light if the frequency of
the pulses exceeds the critical flicker frequency for the design.
The critical flicker frequency employs a number of variables to
determine its exact value but it approximates 120 hertz. Waveform
W2 comprises a frequency of 200 hertz and therefore even though it
is pulsing from "ON" to "OFF" it will be perceived as a steady
light. Its perceived steady intensity will be substantially less
than emitted upper intensity I3.
[0058] FIG. 9 is an intensity versus time diagram--not drawn to
size--of the light emitted from a single led prior art design
emitting light defined as a flicker mode. Looking at FIG. 9
waveform W3 comprises period P8 followed by period P9 which is
followed by a continuous series of similar but random periods not
shown. Period P8 comprises upper intensity zone U8 having upper
dwell time XUP8 emitting light at upper intensity I4. Period P8
also includes lower intensity zone L8 emitting no light--therefore
having zero intensity--and having lower intensity dwell time XLP8.
Period P9 comprises upper intensity zone U9 emitting light at
intensity I4 followed by lower intensity zone L9 emitting no light
and therefore having zero intensity. Emitting at zero intensity
indicates emitting no light. Periods P8 and P9 are generated by a
microcontroller to randomly vary and to have varying upper
intensity and lower intensity dwell times. The lighting device
which includes a waveform such as waveform W3 is described by the
manufacturer as having a flickering mode and that is the perceived
effect achieved by the design. The intensity is perceived as
constantly changing and constantly emitting. This result is
achieved by designing the waveform such that the emitted light is
pulsed at a frequency below the critical flicker frequency for that
design. The waveform for this design indicates periods ranging
between approximately 25 to 50 milliseconds for the varying periods
thereby indicating frequencies varying between 40 and 20 hertz.
Since these frequencies are less than the critical flicker
frequency this prior art light flickers as claimed. It is a good
design for alerting but does not provide the perceived steady light
having a fixed intensity which is necessary to establish the exact
location of the road flares.
[0059] FIG. 10 is not prior art. It is a diagrammatic--not to
size--intensity versus time diagram of waveform W4 depicting a
pulsing waveform which can be substituted for waveform W1 of FIG. 7
in the current invention. Waveform W4 is an alternate waveform of
the current invention. Waveform W4 includes periods P1P and P2P
followed by a continuous series of similar periods not shown.
Pulses K1, K2, K3 and K4 all emit light at intensity I5 within
upper intensity zone U1P of period P1P. Although only four pulses
are identified the actual quantity will differ and will depend upon
the parameters of waveform W4. Period PKU is the period of pulse K2
representative of pulses K1, K3, K4 and all other pulses within
upper intensity zone U1P of waveform W4. Assume that period PKU is
5 milliseconds. Pulses K1 through K4 each emit light at intensity
I5.
[0060] Looking at lower intensity zone L1P pulses K5 through K7 are
identified however the actual quantity of pulses within lower
intensity zone L1P will be a large number. Pulses K5, K6 and K7 all
emit light at intensity I6 within lower intensity zone L1P of
period P1P. Period PKL is the period of pulse K7 representative of
K5, K6 and all other pulses within lower intensity zone L1P of
waveform W4. Assume that period PKL is 5 milliseconds. The upper
intensity zone U1P and the lower intensity zone L1P of period P1P
of waveform W4 each emit within their zones a pulsing light at high
frequencies well above the critical flicker frequency for the
design. Due to the magnitude of periods PKU and PKL the frequency
within the upper intensity zone U1P is 200 hertz and the frequency
within the lower intensity zone L1P is also 200 hertz. In this
design although each zone is actually emitting a high frequency
pulsing light it will, when viewed, be perceived as a steady light.
The perceived intensity of the perceived steady light will be less
than the actual intensity of the light emitted by the individual
pulse. This analysis is identical to that previously discussed
relating to FIG. 8 where prior art employed a series of high
frequency pulses of light to create a perceived steady light.
[0061] Now looking at FIG. 10 period P1P includes high intensity
zone U1P having upper dwell time XUP1P emitting an "ON-OFF" high
frequency pulsing light at intensity I5 followed by lower intensity
zone L1P having lower dwell time XLP1P emitting an "ON-OFF" high
frequency pulsing light at a reduced intensity I6.
[0062] Now looking at both FIGS. 7 and 10 and setting period P1
equal to period P1P, upper dwell time XUP1 equal to upper dwell
time XUP1P and lower dwell time XLP1 equal to lower dwell time
XLP1P it can be seen that the human eye will perceive both
waveforms as emitting light having a stepped intensity and also as
a steady fixed intensity light at each intensity. Period P2P of
waveform W4 having upper intensity zone U2P and lower intensity
zone L2P is similar to period P2 of waveform W1 having upper
intensity zone U2 and lower intensity zone L2. All remaining
periods of each waveform would be similarly related. Hence pulsing
waveform W4 of FIG. 10 can create the perceived stepped intensity
desired of the current invention. Waveform W4 will, like waveform
W1, have a perceived steady light during its lower intensity zone
L1P. It will also have a perceived steady light during its upper
intensity zone U1P.
[0063] Due to the high frequency pulsing characteristic of waveform
W4 the perceived intensities of FIG. 10 will be less than the
emitted intensities I5 and I6. Therefore if intensities I5 and I6
of FIG. 10 are each set to a predetermined value higher than
intensities I1 and I2 of FIG. 7 their perceived values can be made
to equal the perceived intensities of the waveform of FIG. 7 making
light emitted according to waveform W4 the perceived equal of light
emitted according to waveform W1.
[0064] Also, in place of establishing the upper intensity zones of
waveform W4 as a perceived steady light waveform W4, can as
previously described for waveform W1 of FIG. 7, have period PKU
increased to below the critical flicker frequency to create a
perceived flicker effect during upper intensity dwell time XUP1P.
If period PKU is further increased the light emitted during upper
intensity zone U1P of waveform W4 will create a perceived pulsing
effect. Finally, if period PKU is again increased the emitted light
during upper intensity zone U1P will be perceived as a flashing
light. Thus, the periods typified by pulses K1 through K4 can be
selected to effect a flashing, pulsing or flickering effect while
still incorporating the elements of the present invention.
[0065] Also, waveforms W1 and W4 of the present invention continue
to emit light beyond the periods shown in FIGS. 7 and 10 creating a
multiplicity of both upper intensity and lower intensity zones. The
upper intensity zones and the lower intensity zones typically
alternate within the waveforms. The parameters may change as the
waveforms are randomly generated, however the parameters are
limited to achieve the perceived lighting objectives of the present
invention as defined within this specification. The multiplicity of
periods and zones representing the emitted light are mixed and
typically alternate.
[0066] Although designs employing pulsing led light sources at a
frequency exceeding the critical flicker frequency as detailed in
FIG. 8 can improve visibility, are employed in prior art and can be
employed in the present invention for some uses the pulsing design
has deficits relative to the steady emitting configuration of the
current invention as shown in FIG. 7. This results because although
a driver may perceive a high frequency pulsing light as a steady
light when that driver is stationary that same driver can perceive
the light as flickering or pulsing when he is moving. This can
confuse drivers and create accidents. Increasing the pulse
frequency well beyond the critical flicker frequency can ameliorate
this problem. However, employing a design emitting a non-pulsing
steady light avoids the problem.
[0067] Thus the scope of the invention should be determined by the
appended claims and their legal equivalents rather than by the
examples given.
* * * * *